Seamless woven wire sintered well screen

ABSTRACT

The product is a seamless sintered woven wire well screen assembly concentrically mounted on a perforated or slotted mandrel. The seamless sintered woven wire screen can either be used as a component screen apparatus or as a primary screen filter element. In use as a component screen application, the seamless sintered woven wire screen provides a filter reinforcement to a primary filter, or filter housing or shroud device that protects the component screen from physical or mechanical damage during installation. In this configuration two ( 2 ) usually different and separate filter devices are combined. In use as a primary screen element no other means other than the seamless woven wire screen is involved in prohibiting unconsolidated sand production from the wellbore. The well screen relates generally to completing downhole wells, and in particular to well screens for filtering unconsolidated material out of inflowing well fluid in water, oil, gas, and recovery wells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional application No. 60/528,344 filed Dec. 10, 2003.

STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

REFERENCE TO A MICROFICHE APPENDIX

Not applicable.

BACKGROUND OF THE INVENTION

Current embodiments pertaining solely to the utilization of nickel alloy diffusion bonded sintered metal filters in downhole installations are limited to two (2) embodiments. One embodiment uses sintered porous powdered metal which can either be manufactured seamless or press-rolled and welded (U.S. Pat. No. 5,293,935 to Arterbury et.al). In another patent, short sections are welded or mechanically attached (Lowery, Arterbury U.S. Pat. No. 5,318,119) over a perforated or slotted mandrel. Another embodiment in current use involves multi-layered sintered laminate plates calendared together and form-pressed to a tube shape. After forming in a press brake they are seam welded to retain tube shape and strength. In either diffusion bonded (sintered) design they can be employed as a component filter, or as a primary filter.

A problem, which arises with sintered powder well screens, is plugging of sand fines (debris) due to what is known as depth filtration. Uneven pore space openings can cause blockage in specific areas of the filter, which can result in high entrance velocities in others, resulting in erosion and failure.

Another problem that arises in this design is lack of malleability. Sintered porous powder well screens have a tendency to crack and split in bending applications such as those that are encountered in horizontal well bores.

A further problem that arises with sintered laminate tube well screen apparatus relates to the seam welding process. The flat “sheet” metal (which may be woven) is made up of differing layers of filter sheets that are manufactured into a sintered, diffusion bonded single element structure to insure a nominal or absolute filter capability, for example, micron rating, retention etc. In this configuration the sintered laminate well screen tube is seam-welded to maintain shape and integrity. As a result of the press-brake rolling and seam welding processes, many aspects of the procedure compromise the ability of the sintered welded tube to perform in its environment. Seam welded sintered laminate causes a heat affected zone particularly in the region of the weld that can and does create “burn through” by inconsistent heating during the welding process. Pin holes may develop as a result of the process which causes “hot spots” that may evolve into erosion failures. In addition, the heat-affected zone can also be subject to accelerated stress-crack corrosion due to harsh downhole well conditions (ie, temp/chlorides/acid, etc.).

It is also noted that wire-wrapped (conventional) (Smith U.S. Pat. Nos. 3,785,409; 3,908,256; 3,958,634 etc.) well screens are used in the same applications as noted previously. Resistance welding longitudinal ribs to the helically spaced wrap wires constructs these well screens. As previously noted each weld region is susceptible to stress crack corrosion at each juncture due to being heat affected. The control of filter opening (width/pore space) is also compromised at each juncture due to the heat of the welding process combined with the tensile (stretching) conditions placed on the wire during the process. Resistance welded (wire-wrapped) screens are also attached to a base pipe which is perforated or slotted. Connection can either be welded or mechanically attached.

BRIEF SUMMARY OF THE INVENTION

A sand screen assembly for separating particulate material from a subsurface fluid/gas formation uses a well screen having a seamless sintered woven wire element. In one embodiment the element has a seamless sintered woven wire body mounted over a mandrel containing apertures. The seamless sintered woven wire element is placed in a downhole environment in the subsurface gas/fluid formation. Then particulate matter is filtered from the subsurface gas/fluid formation through the seamless sintered woven wire element.

By application of seamless sintered (inter-atomic diffusion) well screen, as opposed to porous powdered sintered or sintered seam welded laminate screen, the principle object of the disclosed embodiments is to exclude the inflow of sand fines in both open hole and cased hole well completions in a more reliable manner.

A related object of the disclosed embodiments is to provide a well screen that offers maximum corrosion resistance for installation in subsurface locations. By way of example, the seamless sintered woven wire body may be electropolished by known electropolishing techniques prior to use. Another object is to provide integral structure through diffusion bonding that ensures accurate pore space openings to coincide with well design parameters. Another object is to circumvent welding at any juncture point. Ductility (malleability) of the metal seamless sintered woven wire body is another improvement over prior art with respect to delamination of the diffusion bonded surfaces which occurs in the prior art devices during expansion and bending of the well screen. Another object is to maintain proportionality between the pore space opening size and changes in the amount or quanta of flexing (bending and/or expansion) of the seamless sintered woven wire body by precision winding to accommodate intentional and/or unintentional changes in form and/or shape which occur downhole. By way of example a fifty percent (50%) expansion of the seamless sintered woven wire body would result in a likewise pore space expansion. All metal to metal crossing points are diffusion bonded without welding in order to attain maximum efficiency in hostile downhole conditions. Due to the absence of seam welding, greater inlet (flow) area is achieved by greater surface filtration exposure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic elevational view of one embodiment of an assembly with a seamless sintered woven wire body well screen in a subsurface environment.

FIG. 2 is an elevational view of one embodiment of a seamless sintered woven wire element.

FIG. 3 is an elevational view of another embodiment of a seamless sintered woven wire element.

FIG. 4 is a close up view of a weave or windings employed in the seamless sintered woven wire element.

FIG. 5 is a view of the device shown in FIG. 4 in an expanded mode.

FIG. 6 is a perspective view of one embodiment of a seamless sintered woven wire body.

FIG. 7 is a simplified schematic view of offset windings.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1 the embodiment disclosed represents a well 10 with surface assembly 11 mounted above ground (or ocean/sea/water body bottom) level 12, an upper tubing string 14 extending subsurface 16, casing 18, a lower production tubing string 20 (either vertical, horizontal or directional) extending into a gas/fluid formation 22 which may contain hydrocarbons, and one or more well screens 30 included in the lower production tubing string 20.

Referring to FIGS. 2-3 the well screens 30 employ a seamless sintered woven wire element 32 which is preferably mounted on a mandrel 34 in contrast to prior art seam-welded sintered laminate/porous well screens for use in various configurations of downhole well completions to reduce produced (inflow) of unconsolidated sand. As a result there are no “seams” or welding lines of prior art devices as wire (various nickel/chrome) alloys are woven onto a usually ceramic or dissimilar metallic mandrel in order to produce a seamless sintered woven wire body 36. The seamless sintered woven wire body 36 is fused by sintering. The sintering process creates a diffusion (inter-atomic) bonded structure.

Referring to FIG. 2, the seamless sintered woven wire body 36 is mounted on the mandrel 34 or pipe 35 with a mechanical type of attachment (such as pinned by set screws or a heat shrink form of attachment 38). Referring to FIG. 3, the seamless sintered woven wire body 36 is mounted on the mandrel 34 or pipe 35 with a non-mechanical type of attachment (e.g via a welded joint 40) Referring to FIGS. 4-5, the weave or windings 50 define pore space openings or inlet areas 52. The pore space openings or inlet areas 52 may be controlled by using precise winding prior to the sintering process. Such control over the pore space/inlet areas 52 surpasses sintered laminate or conventional wire wrapped designs. The winding of the wire 54 performed prior to sintering may be done in an offset (tortuous path) design 50 a (FIG. 7) resulting in an offset flow path generally represented by arrow 51, or a more direct non-offset configuration 50 b (FIGS. 2-6) that is consistent with wire-wrapped screen designs. Offset winding 50 a would be more consistent with component screen products (pre-pack aggregate, etc.) that require fine filtration and “Dirt holding” capacity. Non-offset windings 50 b would be more consistent with wire-wrapped primary screen functions. Filtering characteristics can be affected by wire 54 shape, size, pitch, winding pattern, and winding angle. For example, the helically wound wire 54 in cross section could be “flat” 54 a (FIG. 7) (somewhat trapezoid shaped) or round 54 b depending on the purpose of the application.

A further explanation of the conditions under which well screens are used may help to illustrate the advantages of the seamless sintered wire well screen 30. For largely commercial/economic reasons in the completion design of certain oil/gas/water wells 10 it is imperative to install specialized filtration equipment downhole in order to restrict the inflow of unconsolidated sand. This is usually confirmed by obtaining core (sand) samples of the formation 22 as well as well test data. It is then determined whether filtration will be required downhole in order to maximize productivity of the well 10. The production of sand entrained in or in conjunction with well fluid/gas can cause significant erosion to any equipment (surface and subsurface) in the direct flow path of the well fluid/gas, such as, for example, surface assembly 11. This is known to occur in either a cased hole (perforated) well bore design, or open (barefoot) hole environment. Sand control equipment/treatments are commonly installed in order to prevent the occurrence of produced formation sand. In some cases, chemically bonded porous material (i.e., gravels, proppants) is used to control the inflow of sand. In other cases, either gravel or actual formation sand (open-hole) surrounds a well screening device of sorts. In some cases, a combination (pre-pack screen) of gravel and screen are used in this manner (U.S. Pat. No. 5,339,895). In all of these arrangements or systems, as previously stated, the control or separation of particulate material from subsurface formation fluid/gas is improved by using the sintered seamless woven wire well element 32.

A superior filter body 36 is provided in all applications in regard to life (corrosion resistance), reliability and ductility (bending results in deformation of pore space openings) by way of maintaining the accuracy and precision of winding a continuous shaped or round wire 54 (usually stainless or nickel/chrome alloy) without welding. Diffusion bonding of all crossing sections 56 of the sintered seamless woven wire body 36 insures total integration at the inter-atomic level. High strength levels are attained without compromising accurate filtration efficiencies. An added advantage is that improvements translate directly into economic savings for the operator.

One example of a seamless woven wire device which could be adapted through the disclosure of this application to a seamless sintered woven wire body 36 used in a well screen 30 application is a device commercially available from Fuji America, Inc. known as FUJILOY.

In a preferred embodiment the seamless sintered woven wire body 36 may have one or more of the following features separately or in combination: pore space openings 52 ranging from twenty micron to 1,000 micron; making the body 36 in a tubular shape having a wall thickness 38 (FIG. 6) ranging from 0.020 inches thick to 0.365 inches thick; the seamless sintered woven wire body 36 has pore space openings 52 with tolerances ranging from plus forty microns to minus forty microns; the flat shaped ribbon wire 54 a (FIG. 7) has a thickness ranging from 0.002 inches to 0.150 inches; the round shaped wire 54 b has a diameter ranging from 0.002 inches to 0.150 inches; expanding the seamless sintered woven wire body 36 downhole while proportionately expanding the pore space openings 52 (compare and contrast FIG. 4 to FIG. 5); electropolishing the well screen 30 for corrosion resistance prior to placing it downhole; adding a drainage layer to the well screen 30, by, for example, adjusting the weave 50 during the seamless sintered woven wire body 36 manufacturing process to create variably sized pore space openings according to separate layers 60, 62, 64 (FIG. 7) within the seamless sintered woven wire body 36 (for example the weave 50 could be course next to the mandrel 34, next the weave 50 could be finer, and on the outer weave layer 60 the weave 50 could have large openings). 

1. A sand screen assembly for separating particulate material from a subsurface formation having fluid/gas, comprising: a well screen wherein said well screen comprises a seamless sintered woven wire element.
 2. The sand screen assembly according to claim 1, wherein said seamless sintered woven wire element includes a mandrel having a plurality of apertures and a seamless sintered woven wire body mounted over the mandrel.
 3. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body is made of a flat shaped ribbon wire.
 4. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body is made of a round shaped wire.
 5. The sand screen assembly according to claim 2, wherein a means for mechanical attachment is used for attaching the mandrel to said seamless sintered woven wire body.
 6. The sand screen assembly according to claim 2, wherein a means for welding is used for attaching the mandrel to said seamless sintered woven wire body.
 7. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body has pore space openings ranging from 20 micron to 1,000 micron.
 8. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body is made in a tubular shape having a wall thickness ranging from 0.020 inches thick to 0.365 inches thick.
 9. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body has an offset weave pattern.
 10. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body has a non-offset weave pattern.
 11. The sand screen assembly according to claim 2, wherein said seamless sintered woven wire body has pore space openings with tolerances ranging from plus forty microns to minus forty microns.
 12. The sand screen assembly according to claim 3, wherein said flat shaped ribbon wire has a thickness ranging from 0.002 inches to 0.150 inches.
 13. The sand screen assembly according to claim 4, wherein said round shaped wire has a diameter ranging from 0.002 inches to 0.150 inches.
 14. A method of removing any particulated matter entrained in a subsurface gas/fluid formation, comprising the steps of: obtaining a well screen from a seamless sintered woven wire material; placing the well screen in a downhole environment in the subsurface gas/fluid formation; and filtering the particulated matter from the subsurface gas/fluid formation.
 15. The method according to claim 14, further including the steps of: flexing the seamless sintered woven wire material while maintaining a pore space opening size proportional to the amount of flexing.
 16. The method according to claim 14, wherein said step of making the well screen comprises adjusting a weave to create variably sized pore space openings according to layers within the seamless sintered woven wire material.
 17. The method according to claim 14, wherein said step of making the well screen comprises adding a drainage layer to the well screen.
 18. The method according to claim 14, further including the step of electropolishing the well screen prior to said step of placing the well screen downhole.
 19. A method of removing any particulated matter entrained in a subsurface gas/fluid formation, which comprises the step of filtering a volume of subsurface gas/fluid to remove any particulate matter, wherein the step of filtering is carried out with a device comprising: a seamless sintered woven wire element. 